Carrier route record
DLLAS→BOS
Delta Air Lines · Las Vegas to Boston
- Flights
- 551
- Period
- September 2025 to August 2026
- Share of route
- 35%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on LAS to BOS sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 551 flights, with a median arrival 4 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate Delta on LAS to BOS from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
73.7%
Arrivals under 15 minutes late, of 543 completed flights
Avg delay
77 min
Across delayed arrivals only, not all flights
Cancelled
1.45%
National rate is 1.89%
Whole route
74.6%
Every carrier on LAS to BOS, 1,597 flights
These figures cover 551 flights between September 2025 and August 2026. Beyond the headline rate, 10.9% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Delta against every carrier on LAS to BOS
Delta flew 551 of the 1,597 flights on LAS to BOS, about 35% of it. Its 73.7% on time is about level with the route as a whole at 74.6%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from JetBlue at 75.1% to Delta at 73.7%.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| JetBlue Airways | 1,046 | 75.1% | 95 min | 1.72% | B |
| Delta Air Lines (this page) | 551 | 73.7% | 77 min | 1.45% | C |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When Delta runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 21 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am140 flights62.1%
- 11am–2pm225 flights73.4%
- 2pm–5pm4 flights—
- 5pm–8pm—
- 8pm–5am182 flights83.1%
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is the strongest at 83.1% on time. The full set of windows spans 21 points.
Across the year
Delta on LAS to BOS through the year
July is the worst month at 48.4% on time, 36 points below June, the best at 83.9%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. March was the busiest month here, with 61 flights.
Across the week, Tuesday is the strongest day at 87.0% on time and Monday the weakest at 64.4%, a spread of 23 points.
Arrival by arrival
How late Delta on LAS to BOS runs when it is late
Delta on LAS to BOS often beats the schedule: 163 of 543 completed flights, 30%, arrived 15 minutes or more early. The 143 late arrivals split 44 under half an hour, 40 between 30 and 60 minutes, and 59 an hour or more.
- 15+ min early163 flights30.0%
- Within 15 min237 flights43.6%
- 15–29 min late44 flights8.1%
- 30–59 min late40 flights7.4%
- 1–2 hours late37 flights6.8%
- 2+ hours late22 flights4.1%
Scale runs 0% to 100%.
Share of 543 completed flights by arrival against schedule.
29 of 140 late departures made up the time and arrived on time, 21% of them. In the other direction, 32 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at BOS.
The worst days
Worst days for Delta on LAS to BOS
The latest arrival of the period was on 19 February 2026, 8 hours 14 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 19 February 2026 | 8 hours 14 minutes | Carrier |
| 8 August 2026 | 7 hours 23 minutes | Carrier |
| 30 July 2026 | 6 hours 39 minutes | Late-arriving aircraft |
| 5 January 2026 | 5 hours 34 minutes | Carrier |
| 8 March 2026 | 5 hours 21 minutes | Late-arriving aircraft |
Delay causes
Why Delta runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 11,000 reported delay minutes.
- 42%National Airspace System
- 29%Late-arriving aircraft
- 26%Carrier
- 3%Extreme weather
42% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 4,613 minutes out of 11,000, against a national NAS share of 21%. The split is drawn from 11,034 reported delay minutes.
Cancellations sit at 1.45% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
10.9% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
At 2,381 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 77.5% on time across 551 flights, 4 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 4 points of difference.
One caution: this is a thin sample. 551 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Delta on LAS to BOS
Put together: treat all of this as provisional. 551 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 73.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 543 completed flights over 12 months sit behind that.
Related
Where to go next
- LAS to BOS, every carrier
- Delta on BOS to LAS, the return leg
- JetBlue Airways on LAS to BOS75.1%
- Delta Air Lines network-wide record
- Harry Reid International (LAS) delay statistics
- Boston Logan International (BOS) delay statistics
- The best time of day to fly, according to 7.05 million flight records
- How often a connection fails at the major US hubs
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.